Figure 4.

Levels of neutralizing antibodies against the ancestral SARS-CoV-2 (wild type) and the recently emerged Delta and Omicron variants per subgroup and compared with level of neutralizing antibodies at 6 months. The dotted horizontal line indicates the lower limit of detection of neutralization (titer of 20). P values were calculated using the Wilcoxon signed rank test. Abbreviations: CKD G4/5, chronic kidney disease stages 4/5; KTR, kidney transplant recipient; LLoD, lower limit of dectection; PRNT50, 50% plaque reduction neutralization test.